new inference: distinguish return type type parameters and current session inference variables (IDEA-135001)

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java

@@ -488,7 +488,7 @@ public class InferenceSession {
         if (psiClass != null) {
           LOG.assertTrue(returnType instanceof PsiClassType);
           final PsiTypeParameter[] typeParameters = psiClass.getTypeParameters();
-          InferenceVariable[] copy = initBounds(myContext, typeParameters);
+          InferenceVariable[] copy = initBounds(null, typeParameters);
           final PsiType substitutedCapture = PsiUtil.captureToplevelWildcards(returnType, myContext);
           myIncorporationPhase.addCapture(copy, (PsiClassType)substituteWithInferenceVariables(returnType));
           addConstraint(new TypeCompatibilityConstraint(targetType, substitutedCapture));

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/constraints/WildcardParameterizedReturnTypeConflictWithParameterTypes.java

@@ -0,0 +1,23 @@
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+class Test {
+  private void foo(Function<? super Integer, Stream<Integer>> first) {
+    Function<? super Integer, Object> second = first.andThen(s -> s.map(null));
+  }
+
+
+  private final Function<? super Integer, ? extends Stream<? extends Integer>> first =
+    response -> Arrays.asList(response).stream().map(i -> i++);
+
+  private final Function<? super Integer, ? extends Stream<Map<String, Integer>>> second = first.andThen(
+    mid -> mid.map(i -> {
+      Map<String, Integer> map = new HashMap<>();
+      map.put("key", i);
+      return map;
+    }));
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/ConstraintsInferenceMiscTest.java

@@ -58,6 +58,10 @@ public class ConstraintsInferenceMiscTest extends LightDaemonAnalyzerTestCase {
     doTest(false);
   }
 
+  public void testWildcardParameterizedReturnTypeConflictWithParameterTypes() throws Exception {
+    doTest(false);
+  }
+
   private void doTest(final boolean checkWarnings) {
     doTest(BASE_PATH + "/" + getTestName(false) + ".java", checkWarnings, false);
   }